Lesson 10: Commercial Locksmithing - Part 1

Lock grades


  • Grade 1: Commercial grade locks
  • Grade 2: Residential and light commercial use.
  • Grade 3: Residential use

There are many different types of deadbolts and handle sets available. Each has its own purpose and it’s important to know what that is. One of the distinctions you need to make is about the grade of the lock. The grade of the lock is determined by manufacturer’s standards and refers to testing on 3 factors.

Operational Test: examines the amount of torque needed to retract the latch bolt with and without the key. For key-in-knobs to receive a grade, toque used may not exceed 9 lbf-in. For lever handles, torque may not exceed 28 lbf-in. For all locks, to turn the latch and retract the bolt, torque may not exceed 9 lbf-in.

Strength Test: examines how much turning force a lock in the locked position can withstand. For grade 1, a key-in-knob must withstand 300 lbf-in; a lever lock must withstand 450 lbf-in. For grade 2, a key-in-knob must withstand 150 lbf-in; a lever lock must withstand 225 lbf-in. For grade 3, a key-in-knob must withstand at least 120 lbf-in, and a lever lock must withstand at least 180 lbf-in.

Cycle Test: determines how many the lock can be operated before failure. For grade 1, a lock must complete 800 000 cycles. For grade 2, a lock must complete 400 000 cycles. For grade 3, a lock must complete at least 200 000 cycles.

Colloquially speaking, most locksmiths refer to grades in a tier system: knock offs, residential, commercial, and high-security. High security locks offer the maximum amount of security. These locks have commercial grade durability along with the greatest degree of access control. High security features include exclusive keyways, pick proof locking mechanisms and drill resistant hardware.

Knock off locks don’t have a brand name and are often made offshore. They are made from cheap parts and materials and will not survive an attack or lengthy period of use. As a rule, locksmiths do not carry knock off grade locks in stock. When you encounter them on the job, you should suggest to your customer that they upgrade their locks.

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